西双版纳西南桦人工群落植物区系比较研究

Comparative Study on the Flora of Betula alnoides Plantation in Puwen,Xishuangbanna

在山地雨林采伐迹地更新的13年生西南桦人工林有维管束植物109种，分属59科92属，其科属及其区系成分的数量组成已超过山地雨林（维管束植物有83种，48科76属）。西南桦人工群落科、属的分布区类型组成均以热带分布为主，分别占总科数和总属数的57．63％～60．61％和80．43％～82．15％，科、属分布区类型的温带成分分别占9．09％～11．87％和10．87％～14．28％，说明普文西南桦人工群落植物区系热带性质显著，具有明显的热带北缘性质。研究同时表明，随着森林恢复，西南桦人工群落热带分布成分具有增加趋势，人工林植物区系的丰富度与原生植被和次生植被状况密切相关。

In the Betula alnoides plantation artificially regenerated from tropical montane rain forest （TMRF） logged stand, 109 vascular bundle species, belonging to 92 genera of 59 families, were recorded, which significantly exceeded that of TMRF （ 83 vascular bundle species belonging to 76 genera of 48 families）. For Betula alnoides plantation, the tropical elements respectively contribute to 57.63% - 60.61% and 80.43% - 82.15% at family and generic level of the flora, while temperate element contribute to 9.09% - 11.87% and 10.87% - 14.28% at family and generic level. Thus it is obvious that the flora of Betula alnoides plantation is of tropical in nature. Due to plantation being located at a transitional area of tropical to sub-tropical Yunnan, many tropical plants reach up their northern limit of distribution here. Meanwhile, the research also indicates that flora richness of Betula alnoides plantations closely relate to its regenerated secondary stands and original vegetation. With the succession progress, the tropical distribution elements present increasing trend.